On the size and shape of initial out-of-plane curvatures in structural glass components

► We measure shape and size of initial curvatures of 312 glass beams. ► In general, sinus and parabola describe shape of curvature well. ► Curvature is influenced by lamination and tempering. ► No influence of geometry or interlayer type was observed. ► Characteristic value of initial imperfection amplitude is L/400. For many structural glass components, buckling is known to be a major design issue, which is influenced significantly by several parameters. The latter include boundary conditions, slenderness and geometrical imperfections, in particular initial curvatures. However, in spite of their importance for building practice, experimental data for the latter are very poorly documented. Consequently, an extended experimental campaign is presented in which initial curvatures of 312 monolithic and laminated glass beams with a variable length, height, glass thickness, glass type and – wherever applicable – interlayer, have been accurately measured and analysed. Major conclusions have been drawn regarding the shape and the size of initial curvatures.